1. Field of the Invention
The present invention relates in general to a user network and a method for using one or more access systems to establish communication session(s) with remote communications network(s).
2. Description of Related Art
Common acronyms are used in the following description of the prior art and the present invention. For convenience, the following glossary is provided:    AAA Authentication, Authorization and Accounting    AN Ambient Network    AS Active Set    CS Candidate Set    DS Detected Set    GLL Generic Link Layer    GSM Global System for Mobile Communications    HSPA High-Speed Packet Access    LTE Long Term Evolution (for 3G)    MRRM Multi-Radio Resource Management    UMTS Universal Mobile Telecommunications System    xDSL x Digital Subscriber Line    WLAN Wireless Local Area Network
Ambient Networks (AN) is an integrated project which is co-sponsored by the European Commission under the Information Society Technology priority of the 6th Framework Programme (see http://www.ambient-networks.org). The AN project has a goal of providing scalable and affordable wireless networking in an environment which is populated by a multitude of user devices, wireless technologies, network operators and business actors. For instance, the AN project has a goal of enabling a user network to use one or more access systems to connect to a remote communications network. One way that this goal can be satisfied for the AN project and also for existing communication systems is the subject of the present invention.
Referring to FIG. 1 (PRIOR ART), there is shown a block diagram of an exemplary communication system 100 within which there is a user network 102 that utilizes one more access systems 104a, 104b . . . 104n to connect to a remote communications network 106. The user network 102 can be a single device, e.g. a user terminal like a mobile phone or a computer, with access capability provided by one reconfigurable access system or multiple access systems 104a, 104b . . . 104n. Alternatively, the user network 102 can be an interconnection of multiple nodes, like a personal area network or a moving network within a vehicle, where the access capabilities can be provided by the different nodes. The access systems 104a, 104b . . . 104n can be either a wireless access system such as GSM, UMTS, HSPA, LTE, WiMAX, WLAN, Bluetooth, etc. . . . and/or a fixed access system such as Ethernet, CableModem, xDSL, fiber, etc. . . . The availability and capabilities of the individual access systems 104a, 104b . . . 104n can vary over time, e.g. due to movement of the user network 102, changes in load in the access systems 104a, 104b . . . 104n, etc.
As shown, the user network 102 has many different types of possible access connections 108 which can exist with the remote communication network 106 (which has multiple access systems 110a, 110b . . . 110n). As a result, the user network 102 needs to be able to select one or more of these possible access connections 108 to establish one or more communication sessions with the remote communications network 106 (or multiple remote communications networks 106). In accordance with the AN project, the user network 102 has a processor 112 that uses a MRRM entity 114 and a GLL entity 116 to perform this access selection and to help establish the communication session(s) with the remote communications network 106 (or multiple remote communications networks 106). To accomplish this, the MRRM entity 114 maintains a number of different access sets (which are stored in memory 118) that happen to be classified as follows:                Detected Set (DS): is the set of possible access connections 108 that are detected by the user network 102.        Candidate Set (CS): is the set of suitable access connections 108 that can be used for a particular data bearer to the remote communications network 106.        Active Set (AS): is the set of access connections 108 that are used for a particular data bearer that has been established with the remote communications network 106. In the examples hereinafter, the AS contains one access connection 108 which is currently being used as a data bearer to the remote communications network 106.            Note 1: The AS can be further divided into MRRM AS and GLL AS however this separation is not relevant to the present discussion.    Note 2: The user network 102 has one DS and can have multiple CSs and ASs where a CS and an AS would exist for every data bearer which is transporting either user data or control data. For instance, a first CS and AS may exist for a speech transmission which requires a low bandwidth while a second CS and AS may be exist for a video stream which requires a high bandwidth.    Note 3: The exemplary remote communications network 106 shown herein includes two separate nodes 118a and 118b each of which has a base station 120a and 120b and a radio access controller 122a and 122b. In addition, the exemplary remote communications network 106 includes a single MRRM entity 124 and two GLL entities 126a and 126b.     Note 4: For a detailed discussion about the AN project, reference is made to the following documents where the contents of which are hereby incorporated by reference:            Ambient Networks, “Multi-Radio Access Architecture”, Project Deliverable D2-4, December 2005.        Ambient Networks, “Multi-Radio Access Architecture”, Project Deliverable D2-2, January 2005.        Ambient Networks, “Ambient Network Security”, Project Deliverable D7-2, December 2005, (also Annex II of the deliverable).        
The user network 102 and in particular the MRRM entity 114 and GLL entity 116 determines and maintains the possible access connection(s) 108 which can be used to establish the communication session(s) with the remote communications network 106 (or multiple remote communications networks 106). Basically, the GLL entity 116 monitors and observes the availability, capabilities and characteristics of each of the possible access connections 108 with the remote communications network 106 (or multiple remote communications networks 106). Then, the MRRM entity 114 uses this information and determines/validates which of the possible access connections 108 are to be admitted into the DS (in this example it is assumed that all of the possible access connections 108 are added to the DS). The MRRM entity 114 determines which of the possible access connections 108 within the DS are to be admitted into the CS. In addition, the MRRM entity 114 determines which of the possible access connections 108 within the CS are to be used as data bearer(s) for the communication session(s) with the remote communications network 106. During this access selection procedure, the user network 102 can encounter a problem which relates to the level of connectivity (during the DS-CS-AS phases) that needs to be established between the user network 102 and the remote communications network 106. A detailed description is provided next with respect to FIGS. 2-4 (PRIOR ART).
In the access systems 104a, 104b . . . 104n, the basic connectivity element is the access resource (AR). The AR is a resource which could be used for establishing connectivity and transmitting data. An AR can be identified by an AR identity which can be composed of the id of the resource owner such as the network id and a resource specific id such as a cell id in a wireless access system. For instance, the AR identity could be {network id; access type; resource id}. In addition, the AR can be further characterized by AR-related information/AR-descriptor, such as total/occupied/available resources, resource costs, efficiency of the resource usage like a signal-to-noise-and-interference ratio. Basically, the AR corresponds to the underlying physical resources which are associated with the specific access system, e.g. for a UMTS cell it may correspond to available power, a certain number of codes, etc. . . . .
The other connectivity element in the access systems 104a, 104b . . . 104n is the logical connection (LC). The access system 104a, 104b . . . 104n establishes the LC with the other access system 110a, 110b . . . 110n based on the corresponding access resource. For the establishment of a LC, identifiers (sometimes called locators) for that LC are created in the terminating access systems 104a, 104b . . . 104n and 110a, 110b . . . 110n. The setup of the LC can include: (1) reserving radio resources for the LC; (2) performing AAA procedures; (3) establishing LC security associations; and (4) negotiating LC usage policies. Basically, the AR provides the capability to establish the connectivity and the LC is the data bearer on which data could be transmitted.
The establishment of a LC (based on access resources) is referred to as network attachment. FIGS. 2-4 (PRIOR ART) illustrate three exemplary signal flow diagrams 200, 300 and 400 which are provided to indicate that there is a lot of signaling associated with establishing a network attachment. In FIG. 2, the signal flow diagram 200 shows an example of an attachment of a device to a cellular access system (e.g., the 3GPP LTE system described in 3GPP TR 23.882 V.1.2.3 (June 2006)). In FIG. 3, the signal flow diagram 300 shows an example of an attachment of a device to a WLAN network (the signaling shown includes link attachment, authentication, authorization, establishment of a security association for encryption and integrity protection, and IP address assignment). In FIG. 4, the signal flow diagram 400 shows an improved network attachment procedure which was developed by the AN project to help enable seamless connections between systems like the ones shown in FIGS. 2 and 3. These signal flow diagrams 200, 300 and 400 are well known to those skilled in the art and have been provided herein to simply indicate that it takes a lot of time and resources to establish a LC.
In reviewing the signal flow diagrams 200, 300 and 400, it can be seen that there is a problem which needs to be solved and this problem relates to which phase of the access selection procedure should an AR be converted into a LC for selected access connections 108. Again, the AS contains the LC(s) which are associated with existing/active access connection(s) 108. Somewhere, the AS's logical connections(s) have to be established using the access resources in the chain DS-CS-AS. This particular need and other needs are satisfied by the user network and the access selection method of the present invention.